Final answer:
The author's main arguments about Benjamin Franklin's accomplishments highlight his role as an inventor, scientist, and advocate for self-education.
Step-by-step explanation:
The idea unsupported by the author’s main arguments about Benjamin Franklin's accomplishments is B) Signer of the Declaration of Independence. Although Franklin played a significant role in the founding of the United States, his main arguments relate to his accomplishments as an inventor, scientist, and advocate for self-education. The author's main focus is on Franklin's work as an inventor of the Lightning Rod, a Founding Father of the United States, and his status as someone Largely Self Educated.